Exhaust header system

ABSTRACT

THE EXHAUST HEADER SYSTEM IS FOR USE WITH AN INTERNAL COMBUSTION ENGINE, AS FOR INSTANCE WITH THE PORSCHE 911, WHEREIN THE CYLINDERS ARE DIVIDED INTO TWO EXHAUST BANKS. THE SYSTEM COMPRISES A MUFFLER WHICH IS CONNECTED TO EXHAUST CONDUITS FROM THE RESPECTIVE CYLINDER BANKS, WHICH CONDUITS ARE ADAPTED TO PROVIDE SUBSTANTIALLY THE SAME RESISTANCE TO THE FLOW OF EXHAUST GASES THERETHROUGH. NOTWITHSTANDING THE FACT THAT ONE SUCH CONDUIT IS LONGER THAN THE OTHER, THE RESISTANCE IS MAINTAINED SUBSTANTIALLY EQUAL BY VIRTUE OF THE ADDITION OF CERTAIN TURNS OR BENDS IN THE SHORTER ONE. THE MUFFLER IS UNIQUE IN HAVING COAXIALLY ARRANGED INNER AND OUTER TUBULAR MEMBERS AND NOISE ABSORBING MEANS INTERPOSED THEREBETWEEN. THE INNER TUBULAR MEMBER IS PERFORATED BUT THE SEVERAL TUBULAR MEMBERS ARE MAINTAINED STRAIGHT SO THAT THE FLOW OF EXHAUST GASES IS UNIMPEDED AND THE NOISE IS ABSORBED BY THE NOISE ABSORBING MEANS BETWEEN THE TUBULAR MEMBERS.

p 20, 1971 w. A. CHRISTENSEN 3,605,940

EXHAUST HEADER SYSTEM Filed May 12, 1969 O O O O O O O O 0 000000000INVENTOR. WAY/ve- A. Gueurewsew BY wwfw/ Irma/vans United States Patent3,605,940 EXHAUST HEADER SYSTEM Wayne A. Christensen, 1959 Harbor Blvd.,Costa Mesa, Calif. 92627 Filed May 12, 1969, Ser. No. 823,927 Int. Cl.F01n 1/04; F02b 27/00 US. Cl. 18142 5 Claims ABSTRACT OF THE DISCLOSUREThe exhaust header system is for use with an internal combustion engine,as for instance with the Porsche 911, wherein the cylinders are dividedinto two exhaust banks.

The system comprises a muffler which is connected to exhaust conduitsfrom the respective cylinder banks, which conduits are adapted toprovide substantially the same resistance to the flow of exhaust gasestherethrough. I

Notwithstanding the fact that one such conduit is longer than the other,the resistance is maintained substantially equal by virtue of theaddition of certain turns or bends in the shorter one.

The mufiler is unique in having coaxially arranged inner and outertubular members and noise absorbing means interposed therebetween. Theinner tubular member is perforated but the several tubular members aremaintained straight so that the flow of exhaust gases is unimpeded andthe noise is absorbed by the noise absorbing means between the tubularmembers.

The present invention relates generally to exhaust header systems andmore particularly to such systems as used on internal combustion engineswherein the cylinders are divided into several banks.

For various reasons, certain internal combustion automobile engines havetheir cylinders divided into several banks. This is particularly true ofengines such as are used on the Porsche 911 wherein the six cylindersare divided into two banks of three cylinders each.

Such banks are desirable from various standpoints, not the least ofwhich is for the sake of overall efficiency and balanced operation.

Heretofore, exhaust systems have been provided for such dual-bankengines but such systems have been incapable of affording maximumefficiency for the engine and minimum external noise. That is, priorexhaust systems have been unbalanced so that considerably more backpressure was created for one bank of cylinders than for the other. Also,the mufilers of such prior systems have been so constructed that themaximum noise level could not be maintained without subjecting theengine to undue exhaust pressures and inefliciencies.

It is an object of the present invention to provide an exhaust systemfor internal combustion engines which have their cylinders divided intoseveral cylinder banks, wherein the exhaust flow resistance or backpressure is substantially equal for the several cylinder banks.

Another object of the present invetnion is to provide an exhaust headersystem as characterized above which comprises a single muffier and twoexhaust conduits of different lengths, such conduits being individuallyconstructed and adapted so that in spite of different lengths and shapesthe back pressure and exhaust flow resistance therein are substantiallyequal.

3,605,940 Patented Sept. 20, 1971 An object of the present invention isto provide an exhaust header system as characterized above wherein thelonger exhaust conduit has fewer bends than the shorter one so that theoverall flow resistance in such conduits is substantially equal.

Another object of the present invention is to provide an exhaust headersystem as characterized above which comprises a muffler of thestraight-through type having an inner tubular member which is perforatedand an outer tubular member, there being noise absorbing meansinterposed between such tubular members.

A still further object of the present invention is to provide an exhaustheader system as characterized above wherein the noise absorbing meansin the mufiler is cutcreole glas.

An even further object of the present invention is to provide an exhaustheader system as characterized above which is simple and inexpensive tomanufacture and which is rugged and dependable in operation.

The novel features which I consider characteristic of my invention areset forth with particularity in the appended claims. The device itself,however, both as to its organization and mode of operation, togetherwith addi tional objects and advantages thereof, will best be understoodfrom the following description of specific embodiments when read inconnection with the accompanying drawings, in which:

FIG. 1 is a perspective view of an exhaust header system according tothe present invention;

FIG. 2 is a top plan view of the system of FIG. 1;

FIG. 3 is a fragmentary sectional view through the muffer of the system;and

FIG. 4 is a transverse cross-sectional view of the muffler.

Like reference characters indicate corersponding parts throughout theseveral views of the drawings.

Referring to FIG. 1 of the drawings, there is shown therein an exhaustheader system according to the present invention. It comprises a muffler10 having an inlet 12 and an outlet 14. An exhaust pipe 16 one end ofwhich is flared as at 16a is connected to the outlet 14 of muffler 10.

The system further comprises a pair of exhaust conduits 18 and 20 eachof which is adapted for connection to a separate one of two cylinderbanks of an internal combustion engine (not shown).

The subject invention is most suitable for use with those internalcombustion engines which have their cylinders divided into severalcylinder banks, and wherein overall efliciency and top performance is ofprime importance. One such application of dual cylinder banks is foundin the Porsche 911 which is a high performance automobile of the sportor racing type. Not only must the Porche 911 operate efficiently so thatall of the energy of the fuel is converted into propulsion of theautomobile, but the operation of the engine thereof must be balanced andsteady.

The inlet end of conduit 18 is provided with a flange 22 formed ofquarter inch steel plate. Such flange is provided with several mountingholes 24 as well as a through central opening, and is welded to theinlet of conduit 18 so that the through opening is axially aligned withthe internal diameter of the conduit.

Although not mandatory for successful practice of the instant invention,conduit 18 is preferably constructed of two-inch outside diametereighteen gauge rolled steel tubing. It is formed with three ninetydegree bends as at 18a, 18b and 18c and is approximately forty-oneinches in length. A support member 26 between mufiler and conduit 18 isWelded to such members at bend 18a to provide the desired rigidity andstrength for the assembled unit.

Conduit is provided with a flange 28 formed of onequarter inch steelplate on the order of the aforedescribed flange 22. Flange 28 isprovided with several mounting holes and has a central through openingaligned with the internal opening of conduit 20 when flange 28 is firmlywelded to the end of said conduit. Conduit 20, it has been found, shouldbe approximately thirtythree inches in length if the aforementionedconduit 18 is forty-one inches long, and the conduit 20 should have sixbends, five of which are ninety degree bends and one of which is aforty-five degree bend. As shown most clearly in FIG. 2 of the drawings,the ninety degree bends are at 20a, 20b, 20c, 20d and 20e and theforty-five degree bend is at 20f adjacent the collector 32. As in thecase of conduit 18, the conduit 20 may be constructed of twoinch outsidediameter eighteen gauge rolled steel tubing, although the precisedimensions and sizes are not mandatory for successful practice of theinstant invention.

The collector 32 is formed of 16 gauge seamed steel tubing and is soconstructed as to accommodate both of the conduits 18 and 20 as shownmost clearly in FIGS. 1 and 3 of the drawings. As shown in FIG. 3, thecollector 32 provides conduit 18 with a relatively straight flow pathinto the mufller 10. The conduit 20, on the other hand, is brought intothe muffler 10 at a forty-five degree angle thus causing the exhaustgases therefrom to create additional back pressure or resistance at thecollector 32 within conduit 20.

The entire assembly is weld together, the flanges 22 and 28 being weldedsecurely to the ends of conduits 18 and 20, respectively. The conduitsare also firmly welded to the collector 32 as shown at 34. Thecollector, in turn, is welded to the mufller 10 as shown at 36.

As shown most clearly in FIGS. 3 and 4 of the drawings, the muffler 10is formed with coaxially arranged inner and outer tubular members 38 and40. Such members are preferably circular in cross-section as shown mostclearly in FIG. 4 of the drawings.

The inner tubular member 38 is perforated as shown at 38a, and noiseabsorbing material such as cut-creole glas 42 as positioned within theannular space between the tubular members 38 and 40. Althoughsubstantially any type of glass fibers can be used to absorb some ormost of the noise normally encountered with engine exhaust, it has beenfound desirable to use cut-creole glas. This utilizes glass fibers whichare not of continuous length, but rather are cut to certain lengths soas to be arranged at random with respect to each other. The cut glass isthen soaked in a solution resembling creosote to render the same capableof absorbing noises. The name cut-creole glas is a well-known term inthe manufacture of mufliers, and pertains to such short cut glass fiberswhich have been soaked in the particular solution that resemblescreosote.

The outer tubularmember 40 is swedged at its opposite ends to a positionadjacent the inner tubular member 38 and such members are then weldedtogether as shown at 36 and 44. The welding operation at 44 also firmlyand hermetically secures the pipe 16 to the outlet 14 of the muffler.

Although not mandatory for successful practice of the instant invention,it has been found desirable to construct the outer tubular member 40 ofmuffler 10 of sixteen gauge rolled steel having an outer diameter ofapproximately three and three-quarters inches, andto form the innertubular member 38 of eighteen gauge perforated rolled and seam-weldedsteel having a diameter of two inches.

Exhaust pipe 16 is formed with a ninety degree bend as shown at 16b.

The subject exhaust header system is attached to the automobile suchthat the flanges 22 and 28 are connected to the engine at the severalbanks of cylinders respectively. For instance, in the Porche 911 whereinthe six cylinders are divided into two banks of three cylinders each,the conduit 18, by means of the flange 22, is secured or connected tothe engine at one such bank and the conduit 20, by means of the flange28, is secured at the other. The fact that the several cylinder banksare on opposite sides of the engine and yet the several conduits 18 and20 must come together at a single point in order to simultaneously feedinto the common muffler 10, causes the conduits 18 and 20 to be ofdifierent lengths. Thus, the conduit 18, of necessity, is longer thanthe conduit20. However, by placing an additional three-hundredeightydegree loop in the conduit 20, the shorter length of the said conduit 20is afforded additional flow resistance. That is, although the conduit'18 is longer and hence oifers more total resistance to exhaust flowtherethrough, the conduit 20 is provided with additional ninety degreebends to compensate ,for the additional length of conduit 18.

It is thus seen that although the conduits are of difierent lengths, theflow resistance ofiered thereby is substantially equal thus renderingthe exhaust system balanced.

The construction of the muffler 10, per se, is unique in that it issimple and yet effective. It will be noted that the exhaust gases areafforded a straight-through flow since the inner tubular member 38 isprovided without any turns or bends. The unique noise absorbingmaterial, cutcreole glas, causes the noise to be absorbed suflicientlywithout sacrificing any of the desirable results afforded by thestraight-through flow. Such arrangement has been found preferable to theuse of baflies wherein the exhaust gases are required to follow acomplicated circuitous path.

The exhaust gases, of course, are emitted into the atmosphere throughthe pipe 16, the right angle bend 16a having no effect whatever on thebalanced condition of the exhaust header system because it affects bothbanks of cylinders.

It is thus seen that the present invention provides a balanced exhaustheader system wherein noise is sufficiently absorbed to maintain theexterior noise level below the prescribed maximum, and excessiveunbalanced back pressures are not created for the internal combustionengine.

Although I have shown and described certain specific embodiments of myinvention, I am fully aware that many modifications thereof arepossible. My invention, therefore, is not to be restricted exceptinsofar as is necessitated by the prior art and by the spirit of theappended claims.

I claim:

1. Exhaust header system for internal combustion engines, comprising incombination, a muffler having an inlet, an outlet and noise mulflingmeans intermediate thereof, two exhaust conduits of identicalcross-section but of different lengths and shapes and being individuallyadapted for connection with a separate one of several banks of cylindersof said engine, and a collector interposed between said muifier inletand said conduits to cause said longer conduit to have substantiallystraight flow into said mufiler at the inlet thereof and said otherconduit to cause the exhaust gases therein to make approximately aforty-five degree bend in direction of flow into said muffler to therebycause the total resistanceto flow of exhaust gases in said conduits tobe substantially identical. 7

2. Exhaust header system for internal combustion automobile enginesaccording to claim 1, wherein said mufller is formed with coaxiallyarranged inner and outer tubular members and noise absorbing means isinterposed therebetween.

3. Exhaust header system for internal combustion automobile enginesaccording to claim 2, wherein said inner tubular member is formed withperforations to enable noise within said mufller to be absorbed by saidnoise absorbing means between said tubular members.

4. Exhaust header system for internal combustion automobile enginesaccording to claim 3, wherein said noise absorbing means is heatresistant cut-creole glas to prevent burning of said muffier by hotexhaust gases.

5. Exhaust header system for internal combustion automobile enginesaccording to claim 4, 'wherein said inner and outer tubular members arestraight to afford minimum resistance to flow of exhaust gasestherethrough.

References Cited UNITED STATES PATENTS STEPHEN J. TOMSKY, PrimaryExaminer US. Cl. X.R.

